I have been using PHP for the past few months and developed quite a few handy sites. And done a lot of stuff that I never knew how to do. Anyway, I am looking to get a book that I can use as a reference. However I feel I am beyond the basics of database connection, printing to files, updating databases, opening files etc. I want a book that covers some more of the advanced areas of php. Eg. encryption, etc...

Does anyone know a good book for someone like me? I am not a newby so basically I don't want a book that assumes I know nothing about this language. However, a book that does go into the simple things but extends to more advanced topics would be ideal. It would be great if someone could suggest a few good books. Thanks in advance.